Acrylonitrile polymers stabilized with certain beta-hydroxy tertiary amines



Patented June 15, 1954 ACRYLONITRILE POLYMERS STABILIZED WITH CERTAIN BETA-HYDROXY TER- TIARY AMINES George W. Stanton and Forrest A. Ehlers, Walnut Creek, Caliii, Company, Delaware assignors to The Dow Chemical Midland, Mich, a corporation of No Drawing. Application September 4, 1952,

Serial No. 307,911 r 7 Claims. 1

- This invention relates to compositions of matterconsisting essentially of a polymer containing at least 60 per cent of acrylonitrile in the polymer molecule, and a stabilizing agent to protect the polymer from the embrittling or discoloring effects of exposure to light or heat.

Polyacrylonitrile and copolymers containing acrylonitrile as the predominant constituent undergo undesirable physical changes upon prolonged exposure to, light or to heat. The observable symptoms of such changes are embrittlement or discoloration, or both, due, in varying measure to the action of either light or heat. Since the uses to which such polymers are put include the manufacture of molded articles and thin films, either embrittlement or discoloration is to be avoided, if possible. To this end, it would be desirable to provide agents which can be admixed with the polymers to protect them against one or more of the adverse effects of the conditions to which they may be exposed. The provision of stabilized composition of the polymers and such protective agents is the principal object of the present invention.

This object is realized, according to the invention, by mixing with the polymer from 1 to 20, and preferably from to per cent by weight of a beta-hydroxy tertiary amine from the group consisting of l-dimethylaminoethanol, 2-(2-dimethylaminoethoxy) ethanol, l-dimethylamino- 2 propanol, 3 dimethylamino 1,2 propandiol, and 1,3 bis(dimethylamino) 2 propanol. Articles made from the resulting compositions show little or no tendency to discolor upon prolonged exposure to ultraviolet light, and exhibit little of the tendency to become brittle as a result of such exposure, especially when the stabilizer is present at concentrations of 5 per cent or more.

A copolymer of 80 per cent acrylonitrile and per cent isobutylene was prepared in aqueous emulsion, the polymeric particles were coagulated by addition of magnesium chloride solution, and the coagulum was washed and dried. This copolymer was found to be soluble to the extent of over 15 per cent by weight in acetone. In evaluating the various stabilizers, a 15 per cent solution of the copolymer in acetone was prepared, an amount of stabilizer equal to 15 per cent of the weight of copolymer was dissolved in the solution, and films were cast from the solution on glass plates. lhe films were dried in air overnight, then at 70 C. for one hour. The resulting films were mounted near the rim of a horizontal turntable, with half of the fihn covered light tan color, while the covered and unexposed portions of all the films 96, using the white tile standard as a background. Results with typical compounds in the recited class are given below: Reflection meter reading after hrs. in Fadeometer Test Compound (Stabilizers):

None l-Dimethylaminoethanol 1-Dimethylamlno-2-propanol -Dimethylamino-l,Z-propandiol l,3-bis(dlmethylamino)-2-propanol about 70.

over 89.

about 89. D1

0. about 80.

Reflection meter reading after 120 hrs. in Fadeometer Test Compound For contrast (non-stabilizers):

2-Methy1aminoethanol. Diethylaminoethanol. Triethanolamlne about 70.

To determine the effective concentration of stabilizer in the acrylonitrile copolymer, a series gave readings of to i of films was made with varying amounts of dimethylamino ethanol, and the films were exposed as before for 120 hours in the Fadeometer.

Percent by weight (limethylaminoethanol meter reading about 70.

The samples containing 5 per cent or more of the stabilizer were non-brittle, or much less brittle than those containing smaller amounts of stabilizer. The same stabilizer was added in amounts from 5 to 15 per cent by weight to various polymeric bodies in which acrylonitrile was the predominant polymerized constituent, and the products were exposed in a Fadeometer and tested with the reflection meter, with the following results. The products tested were fibers, films or flow moldings.

- Hours Meter Polymer Composition exposed reading Polyacrylonittile (fiber) 454 about 90. 30 Acrylonitrile-60%; Methyl inmate-40%. 166 over 90. Acrylonitrile86%; 'isobutylenelO%; allyl alcohol4% 139 about 89. Acry1onittile-62.5%; Vinyl Acetate-37.5%-.-- 813 Do.

, the weight of polymer, of a compound from the dimethylaminoethoxy) group consisting of dimethylaminoethanol, 2-(2- ethanol, 1 dimethylamino 2 propanol, 3 dimethylamino 1,2 propandiol and 1,3-bis(dimethylamino)-2-propanol.

2. The composition claimed in claim 1, wherein the stabilizer is present in amount of 5 to 15 per cent of the weight of the polymer.

3. The composition claimed in claim 1, wherein the stabilizing agent is dimethylaminoethanol.

4. The composition claimed in claim 1, wherein the stabilizing agent is Z-(Z-dimethylaminoethoxy) ethanol.

5. The composition claimed in claim 1, wherein the stabilizing agent is l-dimethylamino-Z-propanol. a

6. The composition claimed in claim 1, wherein the stabilizing agent is 3-dimethylamino-1,2- propandiol.

'7. The composition claimed in claim 1, wherein the stabilizing agent is 1,3-bis(dimethylamino) Z-propanol. 7

.No references cited 

1. A COMPOSITION OF MATTER THE ESSENTIAL CONSTITUENTS OF WHICH ARE A POLYMERIC BODY CONTAINING AT LEAST 60 PER CENT BY WEIGHT OF ACRYLONTRILE IN THE POLYMER MOLECULE AND, AS A STABLIZING AGENT THEREFOR, FROM 1 TO 20 PER CENT, BASED ON THE WEIGHT OF POLYMER, OF A COMPOUND FROM THE GROUP CONSISTING OF DIMETHYLAMINOETHANOL, 2-(2DIMETHYLAMINOETHOXY) ETHANOL, 1 - DIMETHYLAMINO- 2 - PROPANOL, 3 - DIMETHYLAMINO -1,2PROPANDIOL AND 1,3-BIS(DIMETHYLAMINO) -2-PROPANOL. 